Microwave oven



FIG. 1 is a front perspective view of a microwave oven showing our new design;

FIG. 2 is a right side elevational view;

FIG. 3 is a top plan view;

FIG. 4 is a left side elevational view; and

FIG. 5 is a rear perspective view thereof. 

The ornamental design for a microwave oven, as shown. 